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(No Model.) 2Sheets-Sheet 1. H. WAITE & S. H. BARTLETT.

' MIORQPHONE. No. 316,204. Patented Apr. 21, 1885.

(No Model.) I 2 Sheet-Sheet 2.

H. E. WAITE & S. H. BARTLETT. V

MICROPHONE. No. 316,204. Patented Apr. 21, 1885 I II IIHHIH llllli-lllllilil-IIIIHIH-IIIIHIIH I? mmlmm UNITEDTSTATES PATENT FFICE- HENRY WAITE AND SAMUEL H. BARTLETT, OF NEW YORK, N. Y.

MICROPHONE.

$PE@IFICATIN forming part of Letters Patent No. 316,204, dated April 21, 1885.

Application filed August 28, 1864. lh'o modcl.)

To all whom it may concern.-

Be it known that we, HENRY E. WAITE and SAMUEL H. BARTLETT, citizens of the United States, residing in the city, county, and State of New York, have invented certain new and useful Improvements in Microphones, of which the following is a specification.

Our invention relates to microphones,- and more particularly to that class in which a series of hard carbons are loosely supported in contact with other pieces of carbon and the whole connected to the diaphragm; and it-has forits object to improve the construction of such instruments, whereby they are rendered more effective, and the electrodes are adjustable and easily removable when desired; and to these ends it consists in certain novel constructions and arrangements, as more particularlypointed out hereinafter.

Referring to the accompanying drawings, forming part of this specification, Figure 1 is a plan view of a diaphragm having a series of carbons arranged radially around the center. Fig. 2 is a section of the same. Fig. 3is aplan of another arrangement. Fig. 4 is a section of the same, and Figs. 5 and 6 show our invention as applied to other well-known forms of microphones.

As microphones of this class have been heretofore constructed no means have been employed whereby the blocks of carbon could be readily and easily adjusted in their bearings, and if a carbon should become broken, out of adjustment, or otherwise unfit for use, the supporting parts had to be removed, the changes made, and the parts restored to their normal condition.

One essential feature of our invention consists in providing means whereby the relations of the various carbons can be adjusted without removing any part of the device, and whereby one carbon piece can be quickly substituted for another. Various means of accomplishing this result may be adopted, that shown in the drawings being simple and effective We support the bearing-block of carbon in springclamps, which are secured to the diaphragm in any suitable manner.

In the drawings, A is the diaphragm,which may be of any suitable material or shape, and in Figs. 1 and-2 a central plate, 13, of conducting material is secured by a screw-bolt to the diaphragm, andupon this is secured a number of cylindrical spring-arms, O, by solder or other means. These are arranged around the edge of the plate opposite a corresponding series of cylindrical spring arms or clamp s,D. .Theseare shown as being provided with detents or dowel-pins cl, adapted to enter the body of the diaphragm, and with screw-bolts d, passing through the diaphragm. These spring-arms are adapted to support the blocks of carbon EF, forming the bearings for the cylinders of carbon, G, having reduced ends entering the blocks E F. The outer blocks, F, are all electrically connected by aconductingstrip, E,and by attaching the terminals of the circuit, one to the conducting-strip E and the other to the central plate, B, the current will pass through the electrodes in multiple are From this construction it will be seen that the blocks E. F can be slipped into the spring-supports and adjusted in any desired relation to the central cylinders, G; and if it is desired to remove or replace any of the carbons it can be readily done.

In Figs. 3 and 4 a similar arrangement of carbons is shown, except that instead of a central metal plate and spring-arms a solid block of carbon, H, is used, having bearings for one end of the central cylinders, G, the other ends being supported in' the adjustable carbon blocks F in the clamps D. is provided with a series of toes or projections, h, bearing upon the diaphragm, and is held by a bolt, h. The outerblocks are shown as connected in two series by the conducting-strips I I, and the line terminals are connected one to each strip, so that the current passes through apart of the outerblocks to the central block, and thence-through the remaining blocks out in what is called multiple-series circuit.

In Fig. 5 another arrangement is shown,

The central block 1 wherein the electrodes are arranged in the circuit is connected to the conducting-plates and passes through the carbons in multipleseries circuit.

In Fig. 6 another form is shown, wherein the central row of springs are connected in one series and the two outside rows are electrically connected.

Heretofore it has been common to make the diaphragm of cork or similar material; but we have found that the diaphragm may be made of diiferent material, as wood, and a strip of cork, M, may be placed around the edge on one or both sides, as shown in Figs. 1 and 2, or astrip of cork may be molded around the edge, as shown at N, Figs. 3 and 4, and this forms an elastic bearing for the diaphragm that has been found to be'efficient and satisfactory.

Our invention has been applied to various other forms of telephones without departing from the principle thereof.

Having thus described our invention, what we claim is 1. The combination, with a diaphragm, of a number of carbon cylinders supported in carbon bearings, the said bearings being adjustable with relation to the cylinders, substantially as described.

2. The combination, with a diaphragm, of a number of spring-clamps secured thereto,supporting carbon .blocks, and carbon cylinders supported in said blocks, substantially as described.

3. The combination, with a diaphragm, of a number of spring-clamps for holding carbon bearings,said clamps being provided with pins or projections entering the diaphragm and secured thereto by bolts passing through the diaphragm.

4:. The combination, with a diaphragm,of a solid central bearing-block of carbon secured thereto, said block being provided with toes or projections bearing upon the diaphragm, and electrodes supported by said block, substantially as described.

5. The combination, with a diaphragm, of wood or similar material, of a strip or strips of cork secured around the edges of the diaphragm, substantially as described.

6. The combination, with the carbon cylinders G, of carbon bearing-blocks E F, adjustably supported in relation thereto, substantially as described.

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

HENRY E. WAITE.

SAMUEL H. BARTLETT.

Witnesses:

WM. H. WOODHULL, G. SPARMAN. 

